Waterjet vs laser cutting
Both cut flat parts straight from a digital file, and for a lot of work either would do the job. The right choice comes down to thickness, material and what the edge has to survive. Here is the honest version, from a shop that runs a waterjet and will tell you when a laser is the better call.
| Waterjet | Laser | |
|---|---|---|
| How it cuts | Ultra-high-pressure water carrying fine abrasive erodes the material away | A focused beam melts and vaporises the material along the cut line |
| Heat on the part | None. The cut runs cold, so material properties are untouched | A small heat-affected zone along every edge; usually harmless, sometimes not |
| Thickness in steel | To 150 mm and beyond, with the same edge character throughout | Fast and clean on sheet; past roughly 20 to 25 mm it slows down and edge quality falls away |
| Materials | Almost anything flat: metals of any hardness, and non-metals like stone, glass, rubber and foam | Mainly metals on fibre machines; reflective metals like copper and brass need the right machine |
| Edge off the machine | Smooth, matte, no burrs from heat, no discolouration | Clean on thin sheet; thicker cuts can carry dross and a hardened, discoloured edge |
| Hardened or treated metal | Cuts it without changing the temper | The heat-affected zone can undo hardening or heat treatment at the edge |
| Speed on thin sheet | Slower, so usually costs more per part | Much faster, so usually cheaper per part |
| What drives the cost | Cut length, thickness and abrasive use | Cut length and machine time; thin sheet in volume is its sweet spot |
When laser is the right call
Thin sheet metal in quantity. If your parts are a few millimetres thick, the edge does not need to be pristine and you want the lowest price per part, a laser shop will beat a waterjet on cost almost every time. That is not a weakness of waterjet, it is physics: the laser simply moves faster through thin material.
When waterjet wins
- Thick sections. Past about 20 mm in steel the laser's advantage disappears, and past its limit only the waterjet keeps cutting, all the way to 150 mm.
- Heat-sensitive work. Hardened, tempered or heat-treated parts keep their properties because the cut never heats them.
- Edges that matter. Weld prep, food-grade stainless and visible architectural work all benefit from a cold, clean, uniform edge.
- Awkward materials. Brass, copper and mixed or laminated materials cut the same way everything else does.
Common questions
Is water jet cutting cheaper than laser cutting?
On thin sheet metal, no. A laser cuts thin material much faster, so its price per part is usually lower. Waterjet becomes the cheaper option as material gets thicker, and past the laser's practical limit it is the only option. For heat-treated parts the comparison is moot, because the laser's heat would damage them.
Does waterjet cutting leave a heat-affected zone?
No. The jet cuts with cold water and abrasive, so there is no heat-affected zone at all. The material at the edge is the same as the material in the middle, which is why waterjet is the standard choice for hardened and heat-treated parts.
How thick can each process cut?
A production laser is at its best on sheet up to roughly 20 to 25 mm in steel, slowing and losing edge quality as it approaches that limit. Our waterjet cuts most metals up to 150 mm with the same cold, uniform edge from top to bottom.
Price your part on the waterjet
Upload your file at kerf.au/quote and your price appears in seconds. If laser is the better fit, we will tell you.